36 _ 



19th and 24th. It does not seem to nie plausible that an excessive 

 progress of the ilium should have been accompanied by modifications 

 that rei)r()duce so nearly perfectly the normal conditions. There is 

 an error of the original segmentation." They criticize me because I 

 have considered 764 and 478 as two good instances of irregular seg- 

 mentation. The formulae are respectively C 7, T13, L5, S5(?) and C7, 

 Til, L5 S&C9. Both cases are pretty normal in the general i)lan of 

 the regions, but in both the 1st coccygeal is fused with the sacrum. 

 1 considered it a coincidence, but they know much better and describe 

 all that happened when the ilium was migrating according to Rosen- 

 berg's theory. But now we know that in point of fact the ilium had 

 moved the other way. Their measurements of spines, in which they 

 take the total length as a starting-point, justify them in saying "La 

 hauteur de la partie pr6sacr6e d'une colonne vert6brale reduite par 

 I'ascension exager^e du bassin et particulierement la region thoracique 

 tend, en vertu des lois biologiques de I'accoramodation, a prendre des 

 dimensions normales." They then explain that this compensation may 

 occur in two ways, either by increased height of the vertebrae or by 

 the addition of a cervical rib; as in fact I had already shown. 



While agreeing, almost entirely with Rosenberg as to causes, 

 they do not accept his conclusions. This is the wise course, for it is 

 far more profitable to discuss the causes of present conditions than to 

 prophecy the etiect of these causes- in the future. Taking for granted 

 Rosenberg's assertion that the ilium moves forward during develop- 

 ment and that under exceptional circumstances it may move farther than 

 normal and in other cases not so far, and accepting also in common 

 with all anatomists the existence of a cervical rib in the embryo which 

 later becomes fused, they recognize a tendency of the neck to encroach 

 on the thorax above and of the sacrum to encroach on the lumbar 

 region and the latter on the thorax below. They reduce the possible 

 combinations to the four following: 1) Retardation of both processes 

 in neck and loins ; 2) Exaggeration of both processes ; 3) Exaggeration 

 above and retardation below; 4) Retardation above and exaggeration 

 below. The last one would of course be represented by the i)resence 

 of a cervical rib and of a reduced number of praesacral vertebrae, and 

 this, be it noted, is a condition described by others as concomitant 

 variation of different regions in one direction. They then describe an 

 interesting spine which they consider as just below a perfect case of 

 the last kind. 



Let us now see how these new observations, and especially Bar- 

 deen's, call for any modification of my conclusions. In the main they 



